Rotating the texture
I can think of a couple of reasons this may happen.  When you mix noise into your coordinate space it can offset the object origin by some amount.  You can attempt to counteract this by adjusting the Location on the Mapping node.
In the case that rotation is not working correctly, it may help to add a second Mapping node behind it and do the rotation separately.  I think there is a set order of operations that you must override.